Powerbook 150 - screen is blank

[joe4227@sympatico.ca]

Powerbook 150 that has been working like a charm. Screen suddenly shows nothing. Brightness and contrast seem to work. Backlight is on.

Boots up normally with normal chime.

Need help to troubleshoot the display. I have worked on CRT's, but not LCD's.

:O

 

[Trash80toHP_Mini]

Have you got the Service Source for the PB150?

 

[joe4227@sympatico.ca]

Yes, I haven't found them to be much help. They are pretty vague.

Did Apple not provide actual schematics for these machines?

These are basically swap-out guides for line of sales staff. For example most LCD displays can be repaired, recaped, etc. The guide simply locates the problem assembly and swaps it out for another. That's not actually repair.

And of course get swap out assemblies for this old a machine may be troublesome! (though I believe there lot Casio LCD MD800TT10-C1's out there, even new.

I am suspicious of the cables and contacts. Plastic parts this old are crumbling. It's a shame, because I know this machine is booting normally, though with no display.

Anyway, I did disassemble the display, and did not see any obviously bad elements. Will have to meter test the caps. The back-light is operating normally.

 

[nvdeynde]

You probably won't need an ESR meter to test the capacitors in the LCD: they are all leaking and the contact are corroded too.

It's possible that recapping the LCD panel will bring back the pictures. The LCD cable of the PB150 is much stronger compared to the other powerbooks of the PB100 series so I doubt it's broken. You can test all the leads of the cable for continuity.

Also look for leakage on the PCB under the pram battery. These often go bad in the PB150 and leak on the PCB.

When your powerbook 150 was still working, were you able to cold start it from the battery ?

Mine works fine but won't cold start from his battery, eventhough it has a new Pram battery. Once it's started from the power adapter, I can work on the battery. Very weird issue.

 

[LCGuy]

Did Apple not provide actual schematics for these machines?

Nup, the last time they published schematics for *anything* was with the Apple II. Apple's repair procedures have pretty much always been pluck n' chuck, going all the way back to the original Mac.

 

[insaneboy]

it appears my newly acquired 150 has the same issues. won't boot from power adaptor and the screen is blank (backlight works) glad apple used 7.2v power, using a 7.2v NiMH RC car battery to run it

 

[joe4227@sympatico.ca]

In disassembling yesterday, the caps all look like the day they were born. They are all SMT's. No leakage.

The Pram battery is showing about 1.3 volts, likely one cell is dead, again no leakage yet.

I have an uncomfortable feeling that it's the JEDI Interconnect board. The machine came on when I was assembling it at one point, just as I was plugging in the cable between the JEDI and the Motherboard.

The invertor board must be working, as the fluorescent backlight is on.

Without schematics, it would be difficult to troubleshoot it properly. Could have blow the video output chip(s) on the MB, or something on the JEDI board.

Luckily, today I found a 180c on eBay, and managed to get it. So a little step up. I want to keep a 68030 machine running while I am recapping and restoring my Mac IIci.

There was another 150 on eBay a few days ago, sold for parts as the owner did not have the Adapter to test it. But it must be gone, as I can't find it now! If I can find another machine, I can compare volyages, etc between the two...

 

[nvdeynde]

The SMD caps in the PB150 LCD are inside a white plastic housing, so without removing it you can see any leakage.

Anyway, I have restores many powerbook LCD's by replacing all the SMD capacitors in the panel.

The powerbook 150 is 17 years old, replacing the SMD capacitors is routine maintanance after so many years.

 

[insaneboy]

There was another 150 on eBay a few days ago, sold for parts as the owner did not have the Adapter to test it. But it must be gone, as I can't find it now! If I can find another machine, I can compare volyages, etc between the two...

the one with the 140 and 150 together? yeah, I got that one. that 150 was in poor condition and has the same problem as yours... I think both of them were garbage finds, very beat up. but the guy was honest, really did not know what he had. 140 worked(screen has some damage) the HDD is now in my 180 and the 150 had RAM upgrade with the DUO memory adaptor.

It does boot when I give it power to the battery terminals, but the screen is blank(backlight on). inside rear of the case is green with corrosion looks like the logic board got wet maybe... all the boards above the logic board look perfect so it might have been sitting back end down in a puddle? (ports all show a little green, and the power port is dark with corrosion) and it has a light aroma of fried electronics

 

[joe4227@sympatico.ca]

nvdeynde

- I did have the display out. And I removed the white cover on the side where the Fluoro tube is. The caps I saw were visible without disassembling the entire display, as they are on one side in a recess in the white case. (It's the Casio/Acer LCD). Are there more on the back of the LCD itself? I assumed no, due to the thinness?

insaneboy

- No, this was pretty clean looking machine, but the seller had no adapter to fire it up, so was selling for $25. I think it was a "Buy it now" sale, and it must have been snapped right up! One machine, alone.

I tried resetting the PRAM and Power Mgr today. It comes on, backlite, and disk runs through the normal startup. But I am getting NO chimes at all, and no screen detail at all. WHich leads me to wonder - Inverter board is working, as backlite is on. But and I *think* the briteness/contrast are working. So with no sound - leads me once again to suspect the JEDI Interconnect board.

Anybody got hints on troubleshooting the JEDI Interconnect board in the absence of another to swap out?

Or could the problem actually be on the MB?

 

[Trash80toHP_Mini]

You don't need the Jedi Board and extra RAM, just pull both out. If the problem doesn't go away, Jedi's not THE problem, but may still be a problem.

 

[joe4227@sympatico.ca]

Apparently there is more than one "Jedi Board". I have seen photos of and have the card that holds the extra RAM. As far as I know that's the Jedi Ram Adapter.

But the long, thin board that conatins the speaker, and into which the Inverter Board plugs, is also the interconnect between the Screen and the Motherboard.

This one is clearly labelled "Jedi Interconnect Board" in my machine, and it is this one to which I referred above. It's also the one that has the big ribbon cable which connects to the Motherboard, and the keyboard connections.

Without that board, there is no way to connect the video to the screen...

 

[Trash80toHP_Mini]

Aaah! Follow your progress with interest we do.

 

[insaneboy]

150's apple code name is Jedi. hence all the Jedi boards inside. |)

IIRC I have sound and I cleaned the backlight and contrast sliders have to double check on the sound thing. I'm about to give up on this particular machine, already has issues with the power input (have to go through the battery connectors to power up) and the case is not great, lots of broken plastic on the screw mounts. I'll test it again later this week and if I have sound still I'll give you my interconnect board for experimentation (I'd just ask the cost of shipping) if I don't have sound I'll be watching this thread for the solution

 

[bibilit]

May the force be with you

 

[Trash80toHP_Mini]

Take it off your hands gladly, we will. If available, Jedi Memory Adapter appreciated much, it would be. [] ]'>

 

[joe4227@sympatico.ca]

Haven't given up on this machine just yet.

The memory adapter holds the ram mod I bought at a local Apple store many years back. They installed. The machine never recognized the ram. Store is long gone...

I noticed the RAM module is marked "duo" - maybe wrong for that machine. I have another RAM module on the way from evil bay. Will see if it works - IF I can get the screen up!

The machine is worth fixing to me, as it uses IDE drives! The 180c uses SCSI.

Point of all this is actually to port my old software to images on the PB G4 and PC under linux/Windows under Basilisk. So I have to find some way to read original floppies (ALL densities, they are old). The G4 can read 1.4 Meg floppies only. And also to transfer things from the IIci to the other machines.

BTW - does someone know a way to connect the Mac IIci's internal SCSI drive to one of the Powerbooks via the external SCSI connector? Is there an adapter that will let me do that?

With the IIci, I am cogitating on the best way to replace the tin-can capacitors on the MB with the replacement SMC Tantalum caps I got from Trag. Not quite sure of the best way to orient and connect those little square beggars to the old form-factor holes on the MB. Anybody?

 

[Trash80toHP_Mini]

I figured you weren't giving on THE 150, just THAT particular 150. :-/ Are you actively lookin' for another one?

The memory type is correct, the 150 takes Duo Memory Expansion Cards. That's the 150's other strong suit, along with the IDE HDDs.

 

[joe4227@sympatico.ca]

I will look for a good screen first, and possible a "for parts" machine with the Interconnect board.

The main prob with these old machines is the decay of the poor quality plastic. I think Apple was trying use biodegradable stuff.

So the first thing that happens when you start working on them is that the mounting posts crumble, then the hinges. Nothing good epoxy won't patch.

The caps on the LCD are the same type of SMC that Trag uses for recapping, and there aren't very many from what I saw.

Would like to try "troubleshooting the screen. If I knew the pinout, I could use a digital signal pulser to strobe the leads and see if it produces anything on screen.

That would show whether the prob is the screen, of something in the Jedi Connect chain, or possibly the MB...

Should also be able to look at waveforms form the MB, as it does appear to boot. But will have to dig my scope out of deep storage to do that! We moved about a year ago, stuff is still in boxes!